Armed with two large knives, he mowed down pedestrians in a 4x4 on Westminster Bridge, including schoolchildren, then rushed at the gates in front of the Houses of Parliament, stabbing PC Keith Palmer, before being shot dead by other officers.

Amid the carnage, an image of a bystander using a selfie stick - a device intended to allow the person holding it to take a photograph of themselves from a wider angle than if they had their camera or smartphone in their hand - was shared on Twitter, with some users expressing disgust.

Stuart wrote: “Sir, you with the selfie stick, you need that shoving up your arse,” which was retweeted close to 900 times.